canon rumors FORUM

The TTL system went away many years ago, replaced by E-TTL and then E-TTL II. Assuming its TTL compatible as they claim, it would be basically a manual flash for any Canon DSLR. It would be interesting to hear if it is actually compatible with E-TTL II, and thus be able to use the in camera flash menu.

I'm not sure but I think it might well be E-TTL II. Their spec for the 565EX also just says TTL but that one is certainly E-TTL II and/or i-TTL.

It doesn't say if their radio system is cross-compatible with Canon's though.

I'd avoid buying one on the assumption that they do not mean what they say. I'd bet its not compatible with the Canon RF link. Canon will have tight security on their RF linkage.

I'd say they use the TTL moniker to embrace the various TTL flavours of individual manufacturers. As for compatibility with Canon's 600EX-RT, not one of the aftermarket brands has cracked their code yet, but since Canon asks an arm and a leg for the unit, there's definitely some space for 3rd party offers.

That said, Yongnuo's set is clearly aiming at people currently without a flashgun, but there are others if you need radio TTL (chinese, pocketwizard etc.).

I wouldn't knock it down until someone gets 3-4 of these guns out in the field and proves their worth (for a fraction of Canon's price).